The widespread use of fossil fuels and related industrial emissions have led to an increase in air CO2 emission year by year and the greenhouse effect caused by CO2 has obviously started to affect a normal living environment of all mankind. Therefore, it is of great significance to detect a concentration of CO2 in the air rapidly and accurately for improving the living environment. In addition, accurate detection of CO2 concentrations is also of great value to many industries. For example, detecting a CO2 concentration in greenhouses can effectively increase a crop yield in agricultural production; detecting a CO2 concentrations can help reduce respiratory disease and improve people's health level in a health system; detecting a CO2 concentration in volcanic gas can effectively predict a volcanic eruption cycle; detecting a CO2 emission from production equipment can indirectly monitor an operation of equipment and improve a production efficiency. In all, a rapid and accurate detection of a CO2 concentration is extremely important for the survival of all walks of life and even for the human beings.
CO2 is a colorless, odorless and chemically inert gas, so accurate detection of its concentration is rather difficult. Current detection technologies of CO2 concentration include acid-base titration, gas chromatography, electrochemical and infrared spectroscopy. Wherein the acid-base titration method is extremely cumbersome, and the accuracy is unsatisfactory. So there is almost little application value. Although an accuracy of a result can be obtained by the gas chromatography, a large equipment is required, and sampling steps are complex and difficult to apply to an on-spot detection rapidly. The electrochemical method mainly detects CO2 relying on a change in potential, current or resistance brought by a reaction of CO2 with electrodes. However, this method is slow in speed and easily interfered with by other acid gases or water, and the application is greatly restricted. Infrared spectroscopy is currently the most widely used technique for CO2 detection. It takes advantage of a characteristic absorption of CO2 carbonyl groups and calculates a concentration of CO2 according to the Lambertil's law. It has great advantages such as fast analysis, non-pollution and portability, but it has fatal disadvantages. Since CO has a very similar infrared absorption to CO2, and in some cases it is hard to avoid a generation of CO, an interference caused by CO cannot be eliminated in the infrared spectroscopy, greatly affecting an accuracy of detection. In addition, infrared spectroscopy and electrochemical methods are very sensitive to a moisture content, further limiting their applications. In all, there is an urgent need to develop a new CO2 detection method that can detect a CO2 concentration rapidly and accurately without an interference of CO and water for production, living and scientific researches.